Most of my writing about science at D&T focuses on recently published discoveries in evolution and ecology. It's fun writing, and it coincides neatly with my regular journal reading, and I intend to keep doing it. But I've discovered that when I want to put new work in context, I often need to discuss fundamental concepts of evolutionary biology that aren't necessarily common knowledge, such as genetic drift or sexual selection. However, I rarely have room to explain these concepts in depth within a blog post devoted to something else.
So maybe the solution is to devote some posts to explaining these "basics." I'm going to start with a series of posts on the "Big Four" processes of population genetics. These are the four processes that account, in one way or another, for every change in the frequency of genes within natural populations. In other words, the Big Four account for much of evolution itself. They are:
- Natural selection, changes in gene frequencies due to fitness advantages, or disadvantages, associated with different genes.
- Mutation, the source of new forms of genes;
- Genetic drift, or changes in gene frequencies that arise from the way probability works in finite populations; and
- Migration, or changes in gene frequencies due to the movement of organisms from site to site.
I'll devote one post each to selection, mutation, drift, and migration, discussing classic findings as well as more recent scientific discoveries about each. They'll arrive as my usual mid-week science posts for the next four weeks, and I'll update this post with links to the others as they go online—so if this looks worth following, you can either bookmark this post, or subscribe to D&T's RSS Feed.
Natural selection, mutation, genetic drift, and migration act together to shape the evolution of natural populations. Photo by jby.
Drake JW, Charlesworth B, Charlesworth D, & Crow JF (1998). Rates of spontaneous mutation. Genetics, 148 (4), 1667-86 PMID: 9560386
Kingsolver, J., Hoekstra, H., Hoekstra, J., Berrigan, D., Vignieri, S., Hill, C., Hoang, A., Gibert, P., & Beerli, P. (2001). The strength of phenotypic selection in natural populations. The American Naturalist, 157 (3), 245-61 DOI: 10.1086/319193
Slatkin, M. (1987). Gene flow and the geographic structure of natural populations. Science, 236 (4803), 787-92 DOI: 10.1126/science.3576198
Wright S (1931). Evolution in Mendelian populations. Genetics, 16 (2), 97-159 PMID: 17246615